This invention relates generally to wrap spring clutches used in percussive pneumatic devices, and more particularly to wrap spring clutches used in fluid activated drills in which a lubricating oil is carried into the drill by the fluid, for lubricating moving parts therein.
One of the most disruptive things that can happen to the clutch is for it to be subjected to extreme amounts of oil. When the spring parts are new, the edges of the spring are very well defined. As the clutch begins to wear, the edges of the spring begin to flatten. As the flattened edge gets larger and the surface area increases, the oil trapped between the spring and its mating surface generates a hydrodynamic effect which acts like a bearing. The oil separates the spring from its mating part which reduces the efficiency of the clutch.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.